Table 2

Summary of findings for the effects of knee arthroscopy versus control in patients with degenerative knee disease

Outcome
Timeframe
Study results and measurementsAbsolute effect estimatesCertainty in effect estimates
(Quality of evidence)
Summary
Conservative managementArthroscopy
Short term
 Pain (difference in change from baseline)
3 months
Measured by: different instruments converted to scale of index instrument (KOOS pain subscale)
Scale: 0–100 high better, minimally important difference 12)
Data from 1231 patients in 10 studies
Follow-up 3 months
15.0
Points (mean)
20.0
Points (mean)
HighOn average, knee arthroscopy results in very small extra reduction in pain scores when compared with control
Difference: mean difference 5.4 more
(95% CI 1.9 more—8.8 more)
 Pain (difference in patients who achieve a change higher than the MID)
3 months
Data from 1102 patients in 9 studies
Follow-up 3 months
669
Per 1000
793
Per 1000
HighKnee arthroscopy increases the number of patients with an important reduction in short-term pain by ∼12 in 100
Difference: 124 more per 1000
 Function (difference in change from baseline)
3 months
Measured by: different instruments converted to scale of index instrument (KOOS ADL subscale, Scale: 0–100, high better
minimally important difference 8)
Based on data from 964 patients in 7 studies
Follow-up 3 months
9.0
Points (mean)
14.0
Points (mean)
Moderate
Owing to serious risk of bias, borderline inconsistency and borderline imprecision
Knee arthroscopy may increase function change slightly more than control
Difference: mean difference 4.9 more
(95% CI 1.5 more—8.4 more)
 Function (difference in patients who achieve a change higher than the MID)
3 months
Based on data from 835 patients in 6 studies
Follow-up 3 months
519
Per 1000
653
Per 1000
Moderate
Owing to serious risk of bias
Knee arthroscopy probably increases the number of patients with an important improvement in short-term function ∼13 in 100
Difference: 134 more per 1000
 Quality of life (difference in change from baseline)
3 months
Measured by: EQ-5D VAS
Scale: 0–100, high better minimally important difference 15
Based on data from 120 patients in one study
Follow-up 3 months
8.0
Points (mean)
14.0
Points (mean)
Low
Owing to serious risk of bias, owing to serious imprecision
Knee arthroscopy may have, on average, little or no difference on QoL change, compared with control
Difference: mean difference 6.0 greater
(95% CI 1.5 fewer—13.5 more)
 Pain and function
up to 3 months
Based on data from 316 patients in 3 studies
Follow-up up to 3 months
Three studies evaluated the effects of knee arthroscopy in pain and function using measures that combined these two outcomes together or that could not be pooled. One study reported a difference in change from baseline in the Oxford knee score that favoured arthroscopy by 4.9 points (95% CI 3.61 to 6.20, 114 patients) over steroids injections. A second study reported no differences in the median in an overall self-assessment based on a 7-point ordinal scale (82 patients) when comparing knee arthroscopy to exercise therapy. The third study reported that patients who received intra-articular hyaluronic acid injections reported less pain than patients who received knee arthroscopy (120 patients)Moderate
Owing to serious risk of bias
Knee arthroscopy probably has little or no difference in pain and function when compared with control
Long term
 Pain (difference in change from baseline)
1–2 years
Measured by: different instruments converted to scale of index instrument (KOOS pain subscale minimally important difference 12)
Scale: 0–100, high better
Based on data from 1097 patients in 8 studies
Follow-up 2 years
19.0
Points (mean)
22.0
Points (mean)
HighOn average, knee arthroscopy results in no difference or a very small reduction, in pain
Difference: mean difference 3.13 more
(95% CI 0.17 fewer—6.43 more)
 Function (difference in change from baseline)
1–2 years
Measured by: different instruments converted to scale of index instrument (KOOS ADL subscale minimally important difference 8)
Scale: 0–100, high better
Based on data from 843 patients in 6 studies
Follow-up 2 years
10.0
Points (mean)
13.0
Points (mean)
Moderate
Owing to serious risk of bias and borderline imprecision
On average, knee arthroscopy probably does results in no improvement or a very small improvement, in function
Difference: mean difference 3.16 more
(95% CI 0.48 less—6.8 more)
 Quality of life (difference in change from baseline)
1–2 years
Measured by: EQ-5D VAS, 15D (converted to EQ-5D scale, MID 15)
Scale: 0–100, high better
Based on data from 269 patients in 2 studies
Follow-up 1 year
10.3
Points (mean)
12.4
Points (mean)
HighOn average, knee arthroscopy does not result in an important improvement in quality of life
Difference: mean difference 2.12 more
(95% CI 0.96 fewer—5.21 more)
 Knee replacement
1–2 years
Relative risk: 1.89
(95% CI 0.51 to 7.0)
Based on data from 497 patients in 2 studies
Follow-up 1 year
12
Per 1000
23
Per 1000
Moderate
Owing to serious imprecision
On average, knee arthroscopy does not result in an increase in the risk of knee replacement
Difference: 11 more per 1000
(95% CI 107 more—6 fewer)
 Pain and function
1–2 years
Based on data from 114 patients in one study
Follow-up 1 year
One study measured pain and function using a composite score. The study showed that patients who receive arthroscopy have a change in Oxford knee score 2.6 points higher than patients receiving steroids injections (95% CI 1.14 to 4.06)Moderate
Owing to serious risk of bias
Knee arthroscopy probably has little or no difference on pain and function
  • 15D, the Health Related Quality of Life 15-Dimension questionnaire; ADL, Function in Daily Living; KOOS, Knee injury and Osteoarthritis Outcome Score; VAS, Visual Analogue Scale.